The country has a little over 800,000 people and is domianted by the 2 main ethnic groups:
The Issa, at around 60%, and the Afar, at around 35%. 

The remainder of the country is made up of small groups of Arabs, French, Ethiopians, and even Italian people.
Also keep in mind, the military base personel, although not citizens, do make a noticable presence in everyday society in Djibouti as well.

The Issa people, which can be found more in the southern regions of the country,
are also sometimes just referred to as Somalians, as they are a subclan of the Somali people and speak their own dialect of the Somali languge.
The Afar people, although slightly more distinct, have a very similar culture and language that resembles the Issa people.

These 2 groups pretty much get along, and especially since the majority of them share the same religion, Islam.

About 93% of the country is Muslim, adherring to the Suni branch of shafii school of jurisprudence legal tradition.

The remainder of the country is predominantly Christian.

You can even find some churches in Djibouti City.

Most are Ethiopian Orthodox.

The country is generally tolerant of any religion, but still restricts proselatizing towards muslims.

The official languages of the country are French and Arabic.

However, French is sometimes used more as Djibouti was once a French territory, and they didnt even get their idependence until 1977.

Culture wise, Djiboutians are known for being quite peaceful but VERY talkative.

They will have no problem spending hours bargaining with a vender, or just sitting you down for a casual 5 hour chat.

Although still classified as a "developing country" with a high unemployment rate at over 50%,
the country has been steadily taking measures to alleviate the problem by instituting a wide range of domestic policies.

About a fifth of the national budget goes to education alone.

And in the past few years, the GDP rate has increased every year and today sits at a steady and comfortable 6.5%.
 Buildings are popping up fast, and the new and improved Djibouti-Addis Ababa railway is currently being constructed between them and Ethiopia, costing over 4 billion dollars in foreign investment.

Because of all the interaction with all the military base personel,  Djiboutians are generally more in the loop when it comes to international affairs.

This is also why Djibouti typically holds a very neutral stance when it comes to international drama.
Once again, Djibouti may be small, but everyone seems to be staring at it.

The position of the country is so advantageous that people from all over the world have kept Djibouti on the radar.